Fix unit test style in core/{dom,editing,html}/.

Source/core/dom/MainThreadTaskRunnerTest.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2013 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 19 matching lines @@
 
 #include "core/dom/ExecutionContextTask.h"
 #include "core/testing/NullExecutionContext.h"
 #include "platform/heap/Handle.h"
 #include "platform/testing/UnitTestHelpers.h"
 #include "wtf/Forward.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
 #include <gtest/gtest.h>
 
-using namespace blink;
-
-namespace {
+namespace blink {
 
 class MarkingBooleanTask final : public ExecutionContextTask {
 public:
     static PassOwnPtr<MarkingBooleanTask> create(bool* toBeMarked)
     {
         return adoptPtr(new MarkingBooleanTask(toBeMarked));
     }
 
 
     virtual ~MarkingBooleanTask() { }
@@ skipping 45 matching lines @@
     OwnPtr<MainThreadTaskRunner> runner = MainThreadTaskRunner::create(context.get());
     bool isMarked = false;
 
     context->setTasksNeedSuspension(true);
     runner->postTask(FROM_HERE, MarkingBooleanTask::create(&isMarked));
     runner.clear();
     blink::testing::runPendingTasks();
     EXPECT_FALSE(isMarked);
 }
 
-}
+} // namespace blink